Process of making indoxyl and derivatives.



UNITED STATES ratented March 29, 1904.-

PATENT OFFICE.

' RUDOLF KNIETSOH, PAUL SEIDEL, AND GEORG WILHELM MEISER, OFLUDWIGSHAFENON-THE-RHINE, GERMANY, ASSIGNORS TO THE BADISOHE ANILIN UNDSODA FABRIK, OF LUDWIGSHAFEN-ON-THE- RHINE, BAVARIA, GERMANY, ACORPORATION OF BAVARIA.

PROCESS OF MAKING INDOXYL AND DERIVATIVES.

SPECIFICATION forming part of Letters Patent No. 756,171, dated March29,1904.

Application filed $eptember 9, 1902.

To all whom it may concern:

Be it known that we,RUDoLE KNIETsoH,doctor of philosphy,a subject of theKing of Prussia,'German Emperor, PAUL SEIDEL,doctor of 5, philosophy andchemist, a subject of the King of Saxony, and GEORG W1LHELMM IsER,doctorof philosophy and chemist, a subject of the King of Bavaria, allresiding" at Ludwigshafenon-the-Rhine, in the Kingdom of Bavaria,Em

I pire of Germany, have invented new and useful Improvements inProcesses for the Manufacture of Indoxyl and Derivatives, of which thefollowing is a specification.

It is known that on heating phenyl glycin I or a homologue thereof at ahigh temperature with an alkaline hydroxid or hydroxids,either alone orin admixture, leuco compounds of the indigo series are formednamely,indoxyl or derivatives thereof. We have discovered that 2 alkali-metaloxids L for instance, potassium or sodium oxid or mixtures of these twooxidscan be advantageously used instead of alkali hydroxid to effect theformation of indoxyl or derivatives thereof. We hereinafter employ 5 theterm alkali oxid to mean sodium oxid or potassium oxid or a mixture ofsodium oxid and potassium oxid. For instance,if a phenylglycin salt andsodium oxid be intimately mixed, even at the ordinary temperature, then3 on being treated with water an abundant formation ofindoxyl or indigoresults, whereas if an alkali hydr'oxid is employed a high temperature,as aforesaid, is necessary to bring about this result. Good results areobtained 35 when the aforesaidalkali oxids are employed in the presenceofa suitable diluent, such as alkali hydroxid or an alkali-earth oxid.The

alkali oxids used in our new process can be obtained'in the knownmanner,(see Dammer,

4 Handbuch 6Z8? Anorgcmz'schen O/zemz'e,Vol. II,

' part 2,pages 8 and 116)for example, by heating together sodium andsodium superoxid or potassium and potassium hydroxid or in any otherconvenient manner.

45 The following examples will serve to exemplify the nature of ourinvention,which, how- Seiial No. 122,701:- (No specimens.)

ever, is not confined to these examples. The parts are by weight.

Example 1: Intimately mix together ten (10) parts of phenyl-glycinpotassium salt and fourteen (14) parts of sodium oxid and heat themixture for about one (1) hour at a temperature of about two hundred andfifty degrees centigrade, (250 O.,) while excluding air. When cold,dissolve the melt in water and work it up to indigo.

Example 2: Mix together fifteen (15) parts of caustic potash andtwenty-five parts of an alkaline mixture containing sodium oxid. Thismixture can be obtained, for example, by introducing ten (10) parts ofmetallic sodium into a molten mixture of thirty (80) parts of anhydrouscaustic potash and twenty (20) parts of sodium superoxid. Into theaforesaid mixture of caustic potash and alkali mixture containing sodiumoxid introduce, while stirring, at a temperature of about two hundredand fifty degrees centigrade (250 O.) ten (10) parts of phenyl-glycinpotassium salt and heat for about one (1) hour at a temperature of twohundred and forty degrees centigrade, (240 C.) When cold, work up themelt.

Example 3: Thoroughly free caustic potash from moisture and then convertit into oxid by subjecting it to electrolysis as long as can be donewithout free metallic potassium becoming noticeable or until freemetallic po- 7 tassium is beginning to be formed. Then discontinue theelectrolysis. Mix three hundred (300) parts of potassium hydrate whichhas been so treated with one hundred and fifty (150) parts of anhydrouscaustic soda, heat the mixture to two hundred and forty degreescentigrade, (2&0 (1,) and add thereto 7 one hundred (100) parts ofphenyl-glycin potassium salt and work up the melt.

Example 4:: Into a molten mixture of two thousand (2,000) parts ofpotassium hydroxid, fifteen hundred (1,500) parts of sodium hydroxid,and five hundred (500) parts of quicklime introduce, while stirring, ata temperature of two hundred to two hundred and twenty degreesCentigrade (200 -220 '0.) suflicient metallic sodium to effect theformation of alkali oxid. Then add an intimate mixture of one thousand(1,000) parts of phenyl-glycin potassium salt and five hundred (500)parts of quicklime and maintain the temperature for about one hour attwo hundred and fifty degrees centigrade, (250 C.) When cold, work upthe melt in the known manner. replaced by strontium oxid or barium oxid.

In the foregoing example the quantity of sodium must be so chosen thatno excess is present, the object being merely to produce sodium oxid,and the action of sodium 011 the phenyl glycin is to be altogetheravoided.

Example 5: Melt together four thousand (4,000) parts ofpotassium-hydroxid, fifteen hundred (1,500) parts of sodium hydroxid,and five hundred (500) parts of sodium oxid. Introduce into the melt ata temperature of two hundred to two hundred and twenty degreescentigrade, (200 -220 (1,) while stirring, one thousand (1,000) parts ofphenylglycin potassium salt and one hundred and If desired, thequicklime can be thirty (130) parts of metallic sodium. Heat for aboutone (1) hour at a temperature of two hundred and fifty degreescentigrade (250 C.) and when cold work up the melt.

We claim 7 1. The process of making indoxyl and derivatives thereof bytreating a phenyl-glycin body with an alkali oxid.

2. The process of making indoxyl and derivatives thereof by heating aphenyl-glycin body with an alkali oxid in the presence of a suitablediluent. I

3. The process of making indoxyl and derivatives thereof by heating aphenyl-glycin body with sodium oxid.

In testimony whereof we have hereunto set our hands in the presence oftwo subscribing Witnesses.

RUDOLF KNIETSCH. PAUL SEIDEL. GEORG WILHELM MEISER.

Witnesses:

JOHN L. HEINKE, JACOB ADRIAN.

